Low sudsing alkaline dishwasher detergent

ABSTRACT

ALKALINE DISHWATER DETERGENT BASED ON AN ALKALINE SEQUESTRANT BUILDER, SODIUM SILICASTE, A CHLORINE BLEACH, AND ALCOHOL ETHOXYLATE NONIONIC SURFACTANT AND A MONO- OR DIALKYL ACID PHOSPHATE SUDS SUPPRESSANT.

United States Patent Office 3,630,923 LOW SUDSING ALKALINE DISHWASHER DETERGENT Judith K. Simmons and Everitt A. Kitchen, Cincinnati, Ohio, assignors to The Procter & Gamble Company, Cincinnati, Ohio N Drawing. Filed May 8, 1969, Ser. No. 823,142 Int. Cl. Clld 7/56 US. Cl. 252-99 3 Claims ABSTRACT OF THE DISCLOSURE Alkaline dishwasher detergent based on an alkaline sequestrant builder, sodium silicate, a chlorine bleach, an alcohol ethoxylate nonionic surfactant and a monoor dialkyl acid phosphate suds suppressant.

BACKGROUND Since the introduction of mechanical dishwashing equipment, considerable attention has been directed to the improvement of alkaline dishwasher detergents. To obtain efficient cleaning in mechanical dishwashers, the detergent used therein must be carefully formulated. Such detergents should contain an alkaline sequestrant builder salt, sodium silicate, a chlorine bleach and a nonionic organic surfactant.

In order to provide efficient cleaning, a dishwasher detergent requires an organic nonionic surfactant in addition to the builder salt, silicate and chlorine bleach. It has been difiicult to provide a nonionic surfactant which performs properly in all respects since a dishwasher detergent must not only be low foaming, but also result in cleansed dishes which are free, or substantially free, from spots and film Because of the high agitation in a dishwater there must be little or no foam produced by the detergent since foam inhibits proper cleansing action or can cause overflow problems. Low foam is particularly difiiculty to obtain because of the presence in food soil of foam formers, such as egg-white. Likewise, cleansing in the dishwasher, followed by rinsing and drying, but without spotting or filming, requires very careful detergent formulation. Surfactant biodegradability is also important.

It is, therefore, an object of this invention to provide a dishwasher detergent employing a specific type of a biodegradable nonionic surfactant/ suds suppressant combination. This detergent is low foaming and results in little or no spotting or filming on cleansed dishware.

DESCRIPTION OF THE INVENTION This invention is an alkaline dishwasher detergent composition comprising an alkaline sequestrant builder salt, sodium silicate, a chlorine bleach, as a nonionic surfactant, the condensation product of normal fatty alcohol containing 16 to 19 carbon atoms with from 7.5 to moles of ethylene oxide, and, as a suds suppressant, an alkyl or alkenyl acid phosphate, containing 16 to 18 carbon atoms. This dishwasher detergent is an effective low sudsing cleaning agent but does not, in use in a mechanical dishwasher, result in objectionable spotting or filming of dishware, e.g., glass, china or plastic.

The alkaline sequestrant builder salt is a primary cleaning component of the dishwasher detergent and is employed in an amount ranging from to 75%, prefer- 3,630,923 Patented Dec. 28, 1971 ably 35% to 60%, of the composition. It also sequesters water hardness to preclude deposition of hardness salts on the kitchenware being washed. Organic or inorganic sequestrant builder salts or mixtures thereof can be used. The preferred sequestrant builder salt classes are the alkali metal (e.g. sodium and potassium) inorganic polyphosphates, organic aminopolyacetates and organic polyphosphonates. Specific examples of these preferred builder salts are sodium tripolyphosphate, tetrasodium pyrophosphate, triand tetra-sodium ethylene diamine tetraacetate, trisodium nitrilotriacetate, trior tetra-sodium ethane lhydroxy-l,l-diphosphonate and triand tetra-sodium ethane-1-hydroxy-1,1,2-triphosphonate. Additional examples of such salts are found in Zimmerers US. Pat. 3,351,558, especially from line 64, column 2 to line 38, column 3 which is incorporated herein by reference.

The sodium silicate is employed in the dishwasher detergents also as a primary cleaning ingredient, as a source of alkalinity, as an inhibitor of metallic corrosion and as a protector of glaze on china tableware. It is used in an amount ranging from 5% to 50%, preferably 10% to 25% of the composition and has a SiO :Na O ratio ranging from about 3.611 to about 1:1, preferably from 3:1 to 1:1.

The chlorine bleach component is a compound which contains chlorine in an active form. Such compounds are often characterized as hypochlorite compounds and are well known as a class. The dishwasher detergent should contain 0.5% to 25% of an active chlorine-containing bleaching compound, preferably 1% to 15%. Examples of such compounds are: dichlorocyanuric acid; 1,3-dichloro-5,5 dimethyl hydantoin; N,N-dichlorobenzoylene urea; paratoluene sulfondichloroamide; trichloromelamine; N-chloroammeline; N-chlorosuccinimide; N,N'-dichloroazodicarbonamide; N-chloroacetyl urea; N,N'-dichlorobiuret; chlorinated dicyandiamide; sodium hypochlorite; calcium hypochlorite; lithium hypochlorite; chlorinated trisodium phosphate. Preferred compounds are chlorinated trisodium phosphate and sodium and potassium dichlorocyanurate. The term chlorinated trisodium phosphate is used to designate a composition consisting of trisodium phosphate and sodium hypochlorite in intimate association in a crystalline form. The chlorinated trisodium phosphate can contain from 1% to 5% available chlorine (calculated on the basis of the hydrated material) and may be prepared by the methods of US. Letters Patent 1,555,474 or 1,965,304, or modifications thereof.

The nonionic organic alkyl ethoxylate surfactants employed in the dishwasher detergents of this invention are C -C normal fatty alcohol-ethylene oxide condensates, i.e., condensation products of one mole of a fatty alcohol containing from 16 to 19 carbon atoms with from 7.5 to 10, preferably 9, moles of ethylene oxide. Mixtures of alcohols, such as those in tallow fatty alcohol, are preferred in the condensates. Tallow alcohol usually comprises a mixture of about octadecanol, about 33% hexadecanol and about 2% tetradecanol, but can vary, depending on the tallow source. Small amounts, up to 10% of C C C and C alcohols can be tolerated, but at least of the alcohol should be C C to insure good cleaning without undue sudsing. Tallow type mixtures can range from 1090% C to 9010% C Such condensates are known in the detergent art but are not believed to have been used, prior to this invention,

II/ P R0 OH wherein R is a normal alkyl or alkenyl group containing from 16 to 18 carbon atoms. The mono alkyl or alkenyl acid phosphates can be utilized alone as the suds suppressant or in combination with up to 50% of the dialkyl or dialkenyl acid phosphate. The acid phosphates can be used as such or neutralized with a base such as sodium or potassium hydroxide, to form the corresponding salts. Alkyl and alkenyl acid phosphates which are suitable for use in this invention are monopalmityl acid phosphate, monestearyl acid phosphate, mono tallow-alkyl acid phosphate, distearyl acid phosphate, mono oleyl acid phosphate, dioleyl acid phosphate and the monoand disodium salts thereof. The alkyl or alkenyl acid phosphate component is 50-100% of the monoalkyl or alkenyl and 5 00% of the dialkyl or dialkenyl acid phosphate, preferably 75 to 85% monoalkyl and 25 to 15% dialkyl. Commercially available forms of the acid phosphates may contain small proportions of condensed phosphates such as pyrophosphates, polyphosphates, monoand dialkyl orthophosphates and trialkyl esters.

The proper blending of the alkyl ethoxylates and alkyl acid phosphates described above is essential to achieving the objects of this invention. The characteristics of the alkyl ethoxylate and the alkyl or alkenyl acid phosphate, as well as the proportions in which they are used, are essential to the obtaining of good cleaning, low sudsing, low spotting, low filming and biodegradability. In the alkyl ethoxylate, alkyl chain lengths higher than C result in spotting or filming. Alkyl chain lengths lower than C generally result in unacceptable sudsing and poor spotting and filming. Within the (Z -C alkyl chain lengths, ethylene oxide contents greater than moles result in unacceptable sudsing; ethylene oxide contents lower than 7.5 rnoles result in unacceptable spotting and filming. The level of the alkyl ethoxylate should range from 1.8% to 3.5% of the composition. At levels greater than 3.5%, sudsing is unacceptably high. At levels lower than 1.8%, spotting and filming is unacceptable. In those situations outside of these specified ranges where the suds level is unacceptably high, the suds level could be reduced by adding large amounts of the alkyl acid phosphate suds suppressor if suds level were the only consideration. The use, however, of such large amounts of suppressor results in waxy film caused by deposition of the suds suppressor on dishware, particularly plastic dishware. There fore, there are not only specific requirements for the alkyl ethoxylate nonionic, but the suds suppressor has specific limitations which are interrelated with the alkyl ethoxylate limitations.

The required suds suppression is obtained only when the mono alkyl or alkenyl acid phosphate suppressant is used alone or in admixture with up to 50% of the dialkyl or alkenyl acid phosphate. The alkyl and alkenyl chain length requirements are such that proper suds supression, without spotting or filming, is not obtained with chain lengths less than C or more than. C Moreover, at least 50% of the alkyl acid phosphate must be the mono alkyl or alkenyl acid phosphate to obtain desired suds suppression. The alkyl or alkenyl acid phosphate should be used in a range of 0.3% to 0.5% of the detergent composition in order to achieve the desired results. Amounts less than 0.3% result in too much suds; even with proper alkyl ethoxylate choice; amounts greater than 0.5 result in undue deposition of the alkyl or alkenyl acid phosphate on plastic dishware. The preferred ratio of alkyl or alkenyl acid phosphate to alkyl ethoxylate is in the range of 0.15:1 to 0.16:1.

The compositions of this invention have a pH in the range of 9.7 to 12.1 (measured in 1% aqueous solution) in order to obtain satisfactory cleaning in the dishwasher. They can be prepared by dry-mixing the ingredients or by agglomeration processes such as those described in US. Pat. 2,895,916, Milenkevich, issued July 21, 1959, incorporated herein by reference.

The instant dishwasher detergents can contain minor amounts of optional ingredients such as colorant, perfume, inert salts such as NaCl or sodium sulfate, anti-tarnish agents such as benzotriazole and aluminum salts, enzymes, alkaline agents such as caustic soda, or sodium carbonate, auticaking agents such as urea.

The percentage figures listed above for the ingredients are on a dry basis. In practice the compositions preferably contain significant amounts of water as water of hydration. This water of hydration can be in amounts from 0% to 35% of the composition.

Below are working examples illustrative of the compositions of this invention which should not be considered as limiting. All parts, percentages and ratios used in the specification, examples and claims herein are by weight unless otherwise specified.

EXAMPLE I A dishwasher detergent composition is prepared by the following procedure:

45 parts of anhydrous granular sodium tripolyphosphate and 14 parts of sodium silicate having an SiO :Na O ratio of 2.911 are placed in a mixer and thoroughly mixed.

27.6 parts of water are then added to this mixture and blended in to agglomerate the tripolyphosphate-silicate mixture.

9.7 parts of chlorinated trisodium phosphate (calculated on an anhydrous basis and containing 7.5% available chlorine) are then added to the mixture with agitation. The added water all hydrates into the ingredients of the mixture. The following additives are then blended into the mixture with agitation:

0.4 part of a mixture of monostearyl acid phosphate and 20% distearyl acid phosphate 1 .007 part green colorant, and 2.6 parts of the condensates of one mole of tallow fatty alcohol and 9 moles of ethylene oxide The resultant biodegradable detergent has a pH of 10.6 and cleans soiled tableware effectively in a mechanical dishwasher, but without undue foam, filming or spotting.

The same composition prepared, except replacing the tallow alcohol/ethylene oxide condensate listed with the condensation product of tallow alcohol with 11 moles of ethylene oxide, results in unacceptable sudsing. A similar replacement With the condensation product of one mole of lauryl alcohol with 9 moles of ethylene oxide results in unacceptable sudsing and unacceptable spotting and filming. A similar replacement with the condensation product of one mole of tallow fatty alcohol and 6 moles of ethylene oxide has acceptable low sudsing, but undue spotting and filming in use. The same composition, except with 0.8 part of the stearyl acid phosphate had unacceptable filming, particularly on plastic dishware.

1 The steuryl acid phosphates are neutralized iu situ to form the sodium salts.

EXAMPLE II The following dishwasher detergent is prepared by dry mixing the listed ingredients.

Percent Sodium tripolyphosphate (anhydrous basis) 45 Potassium dichlorocyanurate 3.5

Condensation product of one mole of tallow fatty alcohol and nine moles of ethylene oxide 2.6 Mixture of 50% mono stearyl acid phosphate and 50% distearyl acid phosphate as the sodium salts 0.4 Sodium meta silicate (having an SiO :Na O ratio of 1:1) Sodium sulfate 15.5 Water, as water of hydration in the sodium tripolyphosphate which was prehydrated before admixture Balance The resulting composition is an excellent alkaline biodegradable dishwasher detergent having a pH of 11.6 in 1% aqueous solution. It cleans soiled dishes very well at a low suds level in a mechanical dishwasher, resulting in no noticeable filming or spotting of china, glassware, or plastic dinnerware of dishwasher parts.

The following are additional examples of dishwasher detergents which clean soiled tableware in a mechanical dishwasher at low suds levels and low levels of spotting and filming. They have pHs of about 10.5.

EXAMPLE 111 Percent Trisodium nitrilotriacetate 50 Sodium silicate having an SiO ZNa O ratio of 2.1:1 15 Potassium dichlorocyanurate 10 Condensation product of 1 mole of octadecanol and 10 moles of ethylene oxide 2 Sodium monostearyl acid phosphate 0.3 Insoluble phthalocyanine green dye 0.005 Water as moisture and water of hydration Balance EXAMPLE 1V Percent Tetrasodium pyrophosphate Tetrasodium ethylenediamine tetraacetate 25 Sodium silicate having an SiO :Na O ratio of 2:1

Sodium dichlorocyanurate Condensation product of 1 mole of a 1:1 mixture of hexadecanol and octadecanol and 8 moles of ethylene oxide Sodium monopalmityl acid phosphate 0.5

Sodium silicate having an SiO :Na O ratio of 2.6:1 15 Calcium hypochlorite 10 Condensation product of 1 mole of octadecanol and 9 moles of ethylene oxide 2 Potassium monostearyl acid phosphate 0.35

Water of hydration and moisture Balance What is claimed is:

1. An alkaline dishwasher detergent composition consisting essentially of:

(a) 25% to alkaline sequestrant builder salt selected from the group consisting of an inorganic polyphosphate, an organic aminopolyacetate, and an organic polyphosphonate,

(b) 5% to 50% sodium silicate having an SiO :Na O

ratio ranging from about 3.6:1 to about 1:1,

(c) 0.5% to 25 active chlorine containing bleaching compound selected from the group consisting of chlorinated trisodium phosphate, sodium dichlorocyanurate, and potassium dichlorocyanurate,

(d) 1.8% to 3.5 condensation product of 1 mole of fatty alcohol containing 16 to 19 carbon atoms with 7.5 to 10 moles of ethylene oxide, and

(e) 0.3% to 0.5% of an acid phosphate compound selected from the group consisting of z (1) an alkyl acid phosphate containing 16 to 18 carbon atoms,

(2) an alkenyl acid phosphate containing 16 to 18 carbon atoms,

(3) sodium salts of said alkyl and alkenyl acid phosphates,

(4) potassium salts of said alkyl and alkenyl acid phosphates,

(5) the acid phosphate ingredients described in (1), (2), (3) and (4) in combination with up to 50% of an acid phosphate compound selected from the group consisting of a dialkyl acid phosphate containing 16 to 18 carbon atoms,

a dialkenyl acid phosphate containing 16 to 18 carbon atoms,

sodium salts of said dialkyl and dialkenyl acid phosphates,

potassium salts of said dialkyl and dialkenyl acid phosphates.

2. The composition of claim 1 wherein the amount of builder salt ranges from 35% to 60%; the amount of silicate ranges from 10% to 25%; the amount of chlorinecontaining bleaching compound ranges from 1% to 15%.

3. An alkaline dishwasher detergent composition consisting essentially of:

(a) 25 to 75 sodium tripolyphosphate,

(b) 5% to 50% sodium silicate having an SiO :Na O

ratio ranging from about 3.6:1 to about 1:1,

(c) 0.5 to 25 chlorinated trisodium phosphate,

(d) 1.8% to 3.5% condensation product of 1 mole of tallow fatty alcohol with 9' moles of ethylene oxide, and

(e) 0.3% to 0.5% sodium monostearyl acid phosphate.

References Cited UNITED STATES PATENTS 3,314,891 4/1967 Schmolka et al. 25289 3,338,836 8/1967 Krusius et al. 25299 3,359,207 12/1967 Kaneko et al. 25299 3,3 66,571 1/1968 Cooper et a1 252-99 3,399,144 8/1968 Hathaway et al. 25299 3,429,822 2/ 1969 Grunewald et al. 25299 MAYER WEINBLATT, Primary Examiner US. Cl. X.R. 

